docs: rewrite user docs, fix modal scroll, webhook URL, and sccache

Rewrite all public documentation to be user-facing only:
- Remove deployment, configuration, and self-hosting sections
- Add guide pages for SBOM, issues, webhooks & PR reviews
- Add reference pages for glossary and tools/scanners
- Add 12 screenshots from live dashboard
- Explain MCP, LLM triage, false positives, human-in-the-loop

Fix edit repository modal not scrollable (max-height + overflow-y).
Show full webhook URL using window.location.origin instead of path.
Unset RUSTC_WRAPPER in agent cargo commands to avoid sccache errors.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

compliance-dashboard/src/pages/repositories.rs

@@ -394,11 +394,12 @@ pub fn RepositoriesPage() -> Element {
                                 r#type: "text",
                                 readonly: true,
                                 style: "font-family: monospace; font-size: 12px;",
-                                value: format!("/webhook/{}/{eid}", edit_webhook_tracker()),
-                            }
-                            p {
-                                style: "font-size: 11px; color: var(--text-secondary); margin-top: 4px;",
-                                "Use the full dashboard URL as the base, e.g. https://your-domain.com/webhook/..."
+                                value: {
+                                    let origin = web_sys::window()
+                                        .and_then(|w| w.location().origin().ok())
+                                        .unwrap_or_default();
+                                    format!("{origin}/webhook/{}/{eid}", edit_webhook_tracker())
+                                },
                             }
                         }
                         div { class: "form-group",